Electrode for arc furnaces



July 3, 1934.

P. SOULARY ELECTRODE FOR ARC FURNACE IS Filed NOV. 25. 1932 InventorElie/ fie dazzle/ 7 By w Attorney supplied to the are.

Patented July 3, 1934 UNl'lED STAT ELECTRODE .FOB ARC FURNACES PierreSoulary, Le Perray, France, assignor to LAir Liquide, Societe AnonymePour LEtude et LExploitation Des Procedes Georges Claude,

Paris, France Application November 25, 1932, Serial No. 644,251 In GreatBritain November 26, 1931 4 Claims. (01. 204-31) The present inventionrelates to an electrode used in furnaces, in which a fluid having agreat dielectric strength, such as liquid hydrocarbon, is submitted to afixed or rotary arc, or to disruptive discharges. This electrode isopposite to, and at a little distance from, a hollow electrode, havingsubstantially the same axis and through the interior of which the fluidto be treated is In proportion of their wear, the electrodes are fed oneto the other in order to maintain the small suitable length of the arc,bound to the dielectric strength of the fluid to be treated.

When the electrode, of which the present in-# vention is an improvement,is solid, it is worn in such a manner that a larger and larger projection is progressively formed in its central part, owing to the morerapid wear of the adjacent peripheral parts, which are opposite to thesolid active part of the hollow electrode. Therefore, when the twoelectrodes are fed together to maintain the are at the small desiredlength, this projecting part, even if small, engages in the fluid supplyconduit of the hollow electrode and may provoke short-circuits, if itcomes into contact with this hollow electrode, the wear of which istherefore made irregular.

The present inventionhas particularly for its object to remedy thesedrawbacks; it consists in using, as an electrode situated substantiallyopposite to the hollow electrode, an electrode (that will be alsothereafter called counter-electrode) that is provided with .a centralcavity extending from its active end for a part of its length towardsits *closed end and in which the sections perpendicular to.its'axis,;along its hollow part, made 'ati-difierent distances from itsactive end are identical to the section's'of the opposite electrodeperpendicular to its axisl made at the same distances from the activeend of said electrode.

This counter-electrode is constituted, for example, by a cylindrical rodof carbon bored for a certain part of its length or even by acylindrical tube one of the'extremities of which is provided with a cap,so as to close the interior cavity of .this tube.

Preferably the counter-electrode terminates in a flat face perpendicularto its axis and the hollow electrode terminates also in a flat faceperpendicular to its axis.

The counter-electrode and the hollow electrode constitute a set ofelectrodes in which the active surfaces from which the arc jumps at theextremity of. each electrode are, at each moment of the working of thefurnace, equal and parallel together and perpendicular to the axis ofthe electrodes. The are jumps therefore in a uniform manner between thetwo electrodes and these are equally worn away. Consequently, in spiteof the wear of the electrodes, their active surfaces 69 remainsubstantially parallel and the steadiness of the arc is obtained. Thisparallelism of the active surfaces of the electrodes affords aparticularly important advantage in the case where liquid hydrocarbonsare treated by the are, for c5 the length of the arc is only' a fewmillimetres.

An embodiment of the invention is diagrammatically illustrated, by wayof an example, in the accompanying drawing.

In this drawing. A denotes a cylindrical tubular 79 rod through theinterior of which the liquid to be treated is supplied to the arc whichjumps between this electrode A and an opposite electrode B. Thiselectrode B is a cylindrical rod, coaxial with the electrode A andhaving the same diameter; it is provided with a cylindrical cavity 6,which extends only for a part of its length from its active end and thediameter of this cavity is equal to the inner diameter of the tubularelectrode A. The electrodes A and Bterminate S0 in a fiat annular face,which is perpendicularto their common axis, and constitutes the activepart of these electrodes.

Instead of using the counter-electrode in its hollow form, its cavitymay be filled, before the electrode being used, by a suitable substance,able to be progressively brought away under the influence of the heat ofthe are (or of the current of fluid supplied through the hollow oppositeelectrode) simultaneously withthe wear of the active part of thiscounter-electrode: for example, use may be made of pitch for thispurpose.

When liquid hydrocarbons are to be treated by the arc, it isnotnecessary to previously fill the cavity of the counter-electrode: thiscavity, 9 becomes automatically filled, after the arc is struck, with apasty mass constituted by a mixtureeof the liquid hydrocarbon submittedto the treatmentby the arc and of the carbon formed by the decompositionof this hydrocarbon; this pasty mass is also worn away progressively atthe same time as the active part of the counterelectrode is worn.

Although the wear of theelectrodes generally takes place regularly overtheir whole active face,,- it is possible, with a view to make such wearmore uniform, to impart to one of the electrodes (or to both electrodes)an axial rotary movement, the current supply being efiected by suitablecontact brushes and rings: Further the electrodes may be fixed and thearc could be submitted to the action of a magnetic field such as wouldimpart to the are a rotary movement around the axis of the electrodes.

What I claim is-- 1. Ina set of electrodes for furnaces in which a fiuidhaving a great dielectric strength is submitted to an electrictreatment, a hollow electrode through the interior of which the saidfluid is supplied to the arc, a counter-electrode situated substantiallyopposite to the first electrode and at a small distance from saidelectrode, a central cavity in said counter-electrode extending from itsactive end along a substantially long part of said counter-electrode, asolid part at the rear end of said electrode closing the said cavity,the sections of the said counter-electrode, perpendicular to its axis,made at different distances from its active end along its hollow partbeing identical to the sections of the opposite electrode, perpendicularto its axis, made at the same'distances from the active end of saidelectrode.

2. In a set of electrodes for furnaces in which a fluid having a greatdielectric strength is submitted to an electric treatment, a cylindricalelectrode, a central cylindrical channel extending along the entirelength of said electrode and through which the said fluid is supplied tothe arc, a cylindrical counter-electrode situated at a small distancefrom the first electrode and with its axis in alignment with the axis ofsaid electrode, said counter-electrode having the same transversal shapeas the opposite electrode, a central cylindrical cavity in saidcounter-electrode extending from its active end along a substantiallylong part of said counter-electrode, said cavity having the sametransversal shape as the channel in the first electrode, and a solidpart at the rear endof said counter-electrode closing said cavity.

3. In a set of electrodes for furnaces in which a fiuid having a greatdielectric strength is submitted to an electric treatment, a cylindricalelectrode, a central cylindrical channel extending along the entirelength of said electrode and through which the said fluid is supplied tothe arc, said cylindrical electrode terminating in a flat faceperpendicular to its axis, a cylindrical counter-electrode situated at asmall distance from the first electrode and with its axis in alignmentwith the axis of said electrode, said counterelectrode having the sametransversal shape as the opposite electrode, and terminating in a fiatface parallel to the end face of the first electrode, a centralcylindrical cavity in said counterelectrode extending from its activeend along a substantially long part of said counter-electrode, saidcavity having the same transversal shape as the channel in the firstelectrode, and a solid part at the rear end of said counter-electrodeclosing' said cavity. v

4. In a set of electrodes for furnaces in which a fiuid having a greatdielectric strength is submitted to an electric treatment, a hollowelectrode through the interior of which the said fluid is supplied tothe arc, a counter-electrode situated substantially opposite to thefirst electrode and ata small distance from said electrode, a centralcavity in said counter-electrode extending from its active end along asubstantially long part of said counter-electrode, a substance capableof being worn away in proportion to the wear of said counter-electrodefilling the said central cavity, a solid part at the rear end of saidelectrode closing the said cavity, the sections of the saidcounterelectrode, perpendicular to its axis, made at diffcrent distancesfrom its active end along its hollow part being identical to thesections of the opposite electrode, perpendicular to its axis, made atthe same distances from the active end of said electrode.

PIERRE SOIJ'LARY.

